The present invention relates to electronic musical instrumentation and, more particularly, to a musical instrument in which accompaniment chord voicing is randomly selected and in which melodic information is represented as plurality of tokens independent of chord type and subsequently converted to note parameters appropriate for a preselected chord type.
A number of systems have been proposed for providing accompaniment to the playing of a musical instrument, such as an organ. A rather successful scheme is disclosed in U.S. Pat. No. 4,433,601, issued to Hall, et al. for "Orchestral Accompaniment Techniques." In the patented system, accompaniment is provided for a plurality of "musical styles" selectable by a player. The accompaniment contains chordal, bass and percussion lines integrated together in prescheduled sequences of musical events and stored in tabular form. When a harmony is selected by the player, an appropriate set of instructions is processed sequentially to sound the accompaniment. Harmonies produced by the accompaniment depend upon player input, but the sequences themselves cannot be altered from their prescheduled form. The voicing of chords in the accompaniment is also predetermined by system programming, requiring relatively complex programming to prevent a rigid, mechanical sound.
Another form of automatic accompaniment is disclosed in the above-referenced U.S. patent application Ser. No. 274,606 now U.S. Pat. No 4,508,002. The art existing prior to the method of that application was capable of embellishing a melody by adding notes limited to the chosen harmony notes sounded a preselected musical compass below the melody. Such art was unable to produce fill notes, which were not tones of the harmony recognized by the instrument. This is a drawback when musicians of limited ability and/or dexterity seek to sustain the accompaniment by playing a minimum number of harmony notes. The invention of the referenced application incorporates significant aspects of musicianship into the automated instrument art by providing a system in which fill notes are derived on the basis of the harmonic relationship between a played melody and a recognized chord. Harmonization is achieved through the use of tabular listings of notes which are not limited to the recognized chord. Data storage requirements are minimized through a system of accompaniment note identification based upon musical transposition.
The aforementioned systems enhance the quality of a performed work but often betray their electromechanical origins. The result is a trade-off between improved harmonization and a loss of realism due to the precision with which the accompaniment is performed. This sometimes produces a mechanical and uninteresting musical texture.